Not really needed unless there's space malaria, chance of sickle cell anemia isn't worth it.
True, as malaria becomes less of a problem, this particular mutation no longer provides a survivability bonus in haploid form.
Politics aren't concerned with silly things like consistence and reality and truth... Also, Elizabeth the I of England was called the virgin queen and had like six illegitimate kids. So, who do you think most of her people would believe, some random guy who says he banged her or all the priests and warriors who say she is still "pure?"
Elizabeth I was called The Virgin Queen because she refused to marry, not because she refused to have sex.
I mean I do not want to get too deep into the woods but:
The science and technology to travel to a distant planetary system are barely theoretical concepts to us that we truly do not know how to accomplish right now
The S and T to manipulate genes to prevent birth defects are something we can conceive achieving within a couple/few decades
So ignoring "inbreeding" is super duper within internal logic as compared to astronomical distances traversed in less than 100+ years
Just saying
PEACE
I couldn't help but think of Jim Holden in The Expanse. He had eight parents, all of whom provided some of their genetic material.
I'm not saying she gets slapped in a machine and BOOM, done. I'm saying that maybe the injections do cause a slow restructuring, can take the little steps along the way, celebrating the milestones of her progress until eventually she's who she wants to be, which unless I missed some story points is probably a full XX female.
You don't even have to go that far. Our genital configuration is governed by a small number of alleles that are switched on or off. For instance, male genitalia is triggered by a sequence that is usually on the Y chromosome, but sometimes finds its way to an X, giving rise to an XX individual born with male genitalia. In many cases, it might be possible to just turn certain genes on or off (or inserting a gene sequence), in order to change.
Of course, those expressions are part of fetal development and puberty, but if one can regrow body parts, growing different body parts would also be possible (The Expanse had a few people growing lost arms and had baby-hands for the scene).